A new high-resolution resistivity measurement instrument, developed by ZZ Resistivity Imaging Pty Ltd, was tested within the Coober Pedy Precious Stones Field, located 900 km north-west of Adelaide, to determine its suitability for assisting in opal exploration. The new tool records the ground's electrical resistivity from the surface to a depth of investigation of around 35 m, and results obtained from three selected test sites showed that: - there is a good correlation between resistivity and lithology; - the technique appears to distinguish between areas of low and high opal prospectivity; and - sub-surface geological features considered to be important for controlling opal emplacement can be delineated. It is concluded that the technique may provide a quick, cost-effective method for assessing the opal potential of an opal claim, as well as for locating specific prospecting targets.